1. Field of the Invention
The present invention relates to a wire driver for a wire line and an endoscope. More particularly, the present invention relates to a wire driver for a wire line, with a simplified structure and operable for fine adjustment, and an endoscope.
2. Description Related to the Prior Art
An endoscope is widely used in the medical field for diagnosis. The endoscope includes an elongated tube and a grip handle. The elongated tube is entered in a body cavity of a patient. The grip handle is connected at a proximal end of the elongated tube. The grip handle has an externally operable device, such as an input lever and operation wheel. A movable part, which is disposed at a distal end of the elongated tube, is driven from a considerable distance by manipulating the externally operable device. Examples of the movable part include a guide device (direction changing device) for changing a direction of a medical instrument such as a biopsy device to protrude in a distal direction, and movable lens optics included in a zoom lens system disposed behind a viewing window.
JP-A 2010-136737 discloses a wire driver for push and pull of a wire line to drive the guide device from a considerable distance. The wire driver is incorporated in a side-viewing endoscope for imaging of an object in a lateral direction which is perpendicular to an axial direction of the elongated tube. In the wire driver, the position of the guide device is adjusted for a quick adjustment by transmitting rotation of the input lever to a pulley for a wire line without a decrease in the speed. Then the position of the guide device is adjusted for a fine adjustment by decreasing the speed of rotation, as the rotation of the input lever is transmitted to the pulley by use of gears.
In a view field of the endoscope, the medical instrument should precisely position at a target point of a lesion or the like. However, the guide device must be finely adjusted. In contrast, the find adjustment is not required in the outside of the view field. It is important to shift the guide device rapidly to return the medical instrument from the active position to the inactive position laid down to an instrument channel.
The endoscope according to JP-A 2010-136737 includes a first wheel for the quick adjustment and a second wheel for the fine adjustment. The first and second wheels must be changed over for the quick adjustment and fine adjustment of the guide device, so that operability for the adjustment is not high. Also, the endoscope of this document requires a speed decreasing device for the fine adjustment, so as to complicate the structure for the adjustment.